Which of the following glands is large sized at birth but reduces in size with ageing ?

Options

A. Pineal
B. Pituitary
C. Thymus
D. Thyroid

Explanation

To answer the question "Which of the following glands is large sized at birth but reduces in size with aging?", we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Glands**: The question provides four options: spinal gland, pituitary gland, thymus gland, and thyroid gland. We need to analyze each of these glands in terms of their size at birth and how they change with age.

2. **Examine the Thymus Gland**: The thymus gland is located near the heart and beneath the breastbone. It is known to be quite large at birth.

3. **Understand the Size Change**: The thymus gland decreases in size as a person ages. By the time a person reaches puberty, the thymus has significantly reduced in size.

4. **Review Other Glands**:
- **Pineal Gland**: Located in the brain, its size remains relatively constant throughout life.
- **Pituitary Gland**: Also located in the brain, it maintains a constant size from birth through maturity.
- **Thyroid Gland**: Located in the neck, it does not show significant size reduction with age.

5. **Conclusion**: Based on the analysis, the only gland that is large at birth and reduces in size with aging is the **thymus gland**.

### Final Answer:
The gland that is large sized at birth but reduces in size with aging is the **thymus gland**.

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